This invention concerns a device and method capable of providing high density information storage. It is related to a series of commonly assigned patents using charge transfer complexes in information storage technology. These are incorporated by reference and are as follows:
U.S. Pat. No. 4,371,883--Current Controlled Bistable Electrical Organic Thin Film Switching Device; PA0 U.S. Pat. No. 4,507,672--Method of Fabricating a Current Controlled Bistable Electrical Organic Thin Film Switching Device; PA0 U.S. Pat. No. 4,574,366--Optical Storage and Switching Devices Using Organic Charge Transfer Salts; PA0 U.S. Pat. No. 4,652,894--An Electrical Organic Thin Film Switching Device Switching Between Detectably Different Oxidation States; PA0 U.S. Pat. No. 4,663,270--Multistate Optical Switching and Memory Using an Amphoteric Organic Charge Transfer Material; PA0 U.S. Pat. No. 4,684,598--An Enhanced Optical Sensitive Medium Using Organic Charge Transfer Materials to Provide Reproducible Thermal/Optical Erasure; and PA0 U.S. Pat. No. 4,731,756--Optical Storage and Switching Devices Using Organic Charge Transfer Salts (Cont.). PA0 TCNQ(OMe) PA0 TCNQ(OMe).sub.2 PA0 TCNQ(OMe)(OEt) PA0 TCNQ(OMe)(O-i-Pr) PA0 TCNQ(OMe)(O-i-Bu) PA0 TCNQ(O-i-C.sub.2 H.sub.5) PA0 TCNQ(OEt(SMe) PA0 TCNQ Cl PA0 TCNQ Br PA0 TCNQ ClMe PA0 TCNQ BrMe PA0 TCNQ IMe PA0 TCNQ I PA0 TCNQ(OMe)(OCH.sub.3).sub.2 PA0 TCNQ(CN).sub.2 PA0 TCNQ(Me) PA0 TCNQ(Et) PA0 TCNQ(i-Pr) PA0 TCNQ(i-Pr).sub.2.
All of these patents are based on the electron transfer mechanism of charge transfer complexes, in particular the Metal-tetracyanoquinodimethane (TCNQ) complexes.
In U.S. Pat. No. 4,916,688 entitled "Data Storage Method Using State Transformable Materials", scanning tunneling microscopy is used to selectively melt discrete areas of a state transformable film. This is an amorphous-to-crystalline phase transformation. The thin film is a metal/metal compound material as opposed to a nonstochiometric alloy.